1. Field of Invention
This invention relates generally to motion analysis and specifically to a method for comparing a student""s motion to that of a master in a particular sport such as golf.
2. Description of Related Art
Form and body position are essential to mastering many sports. For example, in golf, proper positioning of the head, hands, and golf club is necessary for a good golf swing. Thus, players wishing to improve their performance often enlist a professional to analyze their technique and offer advice for correcting the player""s position and motion. In addition, there are a number of video training systems available to aid a player in practicing his golf swings. Typically, these systems superimpose a video image of a student practicing his swing over a video template of a master executing a desirable golf swing so that differences between the student""s swing and the master""s swing can be discerned.
For example, one type of training system is disclosed in U.S. Pat. No. 5,333,061 to Nakashima et al in which recorded video images of the student""s swing are converted into still pictures and superimposed over corresponding pictures of a master""s swing consisting of a series of lines connecting various points on the master""s body and club. The resulting pictures are then recorded onto a videotape, and additional visual and/or audio information can then be added to the videotape. Although the resultant superimposition of the student""s swing over the master""s swing is beneficial, the process of making the training video tape is lengthy and, thus, fails to provide immediate feedback to the student. Typically, the video tape is made some time after the student""s swing is recorded, and the student subsequently views the training video in a VCR, for instance, at home. The time delay between the student practicing his swing and viewing the training video often reduces the effectiveness of feedback.
Other systems allow a student to compare his swing with a master""s swing in real time. For example, in U.S. Pat. No. 5,904,484, O""Leary et al use a video overlay generator to produce a static image representing the dynamic technique of a master, and overlay the live image of the student for a simultaneous display on a visual monitor. While watching the overlying image of the master, the student attempts to execute his swing so as to maintain his image in alignment with the image of the master. Another interactive real time training system is disclosed in U.S. Pat. No. 5,904,484 to Burns and allows a student to interactively emulate in real time the dynamic motion of a master performing a selected motion on a monitor simultaneously displaying the student in real time.
Although allowing for real time comparisons to a master, these techniques undesirably require the student to practice the selected motion while simultaneously watching a video monitor. It may be difficult and/or distracting for the student to completely concentrate on his swing motion while watching a video monitor. Further, requiring the student to watch the video monitor may preclude proper positioning and orientation of the head during, for example, a golf swing. Moreover, requiring the student to watch the video monitor may preclude other critical elements of the motion, for example, hitting a ball in a golf swing or baseball swing. Therefore, it would be desirable to provide substantially immediate comparison feedback to a student practicing a swing motion without requiring the student to watch a monitor while practicing the swing motion.
A method and apparatus are disclosed that allow a student to receive immediate analysis of a swing motion such as a golf swing without having to watch a video monitor while performing the swing motion. In accordance with the present invention, a pre-recorded video of a master""s swing motion is stored as a plurality of first frame sequences in computer memory. Target cues indicative of motion progress of some indicia, such as the master""s wrists, are associated with each first frame sequence. A video recording is made of the student performing the swing motion, and stored in computer memory as a plurality of second frame sequences. References cues indicating motion progress of using the same indicia as used for the master, e.g., the student""s wrists, are inserted into or associated with each student frame. In some embodiments, the reference cues are generated by a processor. In other embodiments, the reference cues are generated manually by tracing a motion path of the indicia using, for example, a mouse or touchpad. In one embodiment, the student wears a magnetic glove or other device that allows the student""s wrist to be tracked throughout the swing motion. After the master frames are aligned with and normalized to the student frames, the master frames are synchronized to corresponding student frames using the target cues and the references cues for synchronization. The corresponding master and student frame pairs are superimposed, and displayed as a motion video on a video monitor to allow the student to analyze differences between his swing motion and the master""s swing motion.
The ability to record the student""s video, synchronize it to a master""s video, and immediately display the resultant superimposed video to the student provides students with immediate analysis of their golf swing. Unlike prior devices, the present invention does not require the student to look at a video monitor while executing his golf swing in a manner to emulate a master""s swing, thereby allowing the student to concentrate on executing his swing in a normal manner. Further, since present embodiments provide the superimposed, feedback video directly from computer 11, without having to a make a video tape recording, the student receives immediate, on the spot feedback. Thus, after analyzing his swing, the student may immediately record and analyze another swing. This is in contrast to prior training systems that result in the production of a training video tape which typically must be later viewed by the student in a VCR, perhaps at home.